Developments toward radiation dose assessment using next generation polygon human phantoms

Furuta, Takuya   ; Sato, Kaoru   ; Takahashi, Fumiaki  

Voxel-based computational human phantoms have been used for radiation dose assessment with Monte Carlo radiation transport simulation codes. However, development of polygon-based computation humans becomes popular due to advantages on description of thin layer tissues and small organs. International Commission on Radiological Protection (ICRP) also announced to adopt polygon human phantoms as the reference phantoms. We therefore introduced a function to treat tetrahedral-mesh geometry, a type of polygon geometry, into Particle and Heavy Ion Transport code Systems (PHITS). Along this implementation, we also developed an efficient transport algorithm with tetrahedral-mesh geometry, which allows to reduce the computational time to 1/4 of the voxel-mesh calculation using the same precision computational human phantom. We also started a development of new polygon-based human phantoms based on Japanese voxel phantoms. The complete version will be published hopefully next year.